Telemeter



LSGBB?? Auge 3.9 9 R924.,

O. EPPENSTEIN TELEMETER Filed Aug. 13 1921 Patented itig;., i 1924.

UETED STATES PATENT OFFICE.

OTTO EPPENSTEIN, OF JENA, GERMANY, ASSIGNOR TO THE FIRM OF CARL ZEISS, OF

^ JENA, GERMANY.

TELEMETER.

Serial No. 492,106. VV

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L., 1313.)

To all 'whom it may concern Be it known that I, OTTO Err-Ns'rEiN, a citizen of the Ge man Empire, residing at Jena, Germany, have invented a new and useful Teleineter (for which I have filed an application in Germany, August 9, 1918), of which the following is a specification.

The present invention relates to a telemetedestined for measuring the range from air-Crafts and provided with a deflecting device. allowing of altering the relative position of two images ot' the object to bemeasured, which are presented to the observer.

l`he object ot' the said invention is to construct the telemeter in such a Way that on a range scale, coupled to the defiecting device ot' the telcneter, the range from the object to be measured is correctly indicated in each particular case, provided the defiecting device has been adjusted for the object to be measured and that, by altering the elevation of the telemeter, the adjustment of the deflecting device is automatically modified in such a way that the relative position of the two images, presented to the obscrver, remains stationary in the direction of the baseline, When the tclemeter, With an invariable height of the object to be measured, is directed to it.

In the annexed drawing Fig. l shows a model of the theoretical principle of the invention. whilst Figs. 2 and 3 illustrate a constructional example. Fig. 2 is partly a front view, partly a section on the line 2-2 ot Fig. 3. Fig. 3 is a plan elevation.

For this purpose the new telemeter has been constructed as follows: The one of the two crown wheels of a diferential gear is so coupled to a body, the position of which relative to the Vertical line is invariablc, that, when altering the elevation of the (clcneter, the deflcction of the said crown wheel tron a certain original position is always p'oportional to the logarithm of the sine of the angle ot' sight of the object just observed, whereby the angle of sight is reckoned from the horizontal direction of look-out. In addition, the other of the two crown wheels is so coupled to the defiecting device that its reflexion from a certain original position is always proportional to the logarithn of the range, which is indicated in each particular case on the range scale of the telemeter accordng to the position of the deflecting device. Finally, the planet 5 pinion of the ditlcrent-ial gear is coupled to an actuating device, allowing of rotating the planet pinion about the joint axis of the crown wheels. Let the height of an object X above the horizontal plane, containing 80 the observer Y, be denoted by A (vide Fig. 1 ot' the annexed drawing), the distance of the object from the observer by B and the angle of sight of the object by a. If the tclemeter be adjusted at any angle of sight 6 a, the rotation 6, of the first crown Wheel from its original position is proportional to the sine of the angle of sight, hence it is 6,:M log sin or, M, being a constant. If, at the same time, any range be indicated on the range Scale, the second crown Wheel has a rotation 6,, according to the equation 6,:M log B, M again being a constant. r It' may be taken since the longitudinal unit, on which the range is to be' based, is optional. The deflexion 6 of the planet pinion from its original position is according to the equation 6,:M,(log sin oz+log B),

therefore log Azlog sin oc-l-log B,

consequently zM log A. The position of the planet pinion is, therefore, roportional to the height of the object observed. By adding to the planet pinion a logarithnic height scale of a corresponding size, it is even possible to read off on the same the height of the object to be measured. Inversely, by securing the planet pinion and by directing the telemeter to an object, which moves at the height, corresponding to the position of the planet pinion, the distance of the respective `object is continuously and correctly indicated on the range scale and consequently the deflecting device is also continuously so adjusted that its adjustment corresponds to the distance of the object in each particular case. If, therefore, the actuating device 'of the planet pinion be stopped, or if the said device beso devised as 'to stop automatically, the telemeter fulfils the above mentioned task. As the logarithm of the sine of the angle of sight would assume for the value zero of the angle of sight the value -a, the telemeter cannot be constructed according to the invention for very small angles of sight; for corresponding reasons the range of distance, within 'which the telemeter is devised according to ,the invenvice in elevation which is well suited for' angle of sight.

the' requirements of the observation of aircrafts." For, the sa.id .;c'rown wheel'being so coupled to the invariable body that its deflection is roportional to the logarithm of the 'sine of the angle `of sight, the alterations of deflection, corresponding to the same alterations of the angle of sight with a small angle of sight are large in comparison with those'with a large angle of sight, inve'sely, to the same displacements of the actu'ating device of the crown wheel with a small angle of sight, there correspond alterations of the angle of sight, which are small in comparison with those with a large needs of observation'of air-crafts, inasmuch sary, when using as with. an invariable speed 'of an air-craff, moving at one and the same height, the angle of sight changes the faster, the larger it grows. V

If 'the objectto be observed moves at approximately one and the same hei ht, according to the object of the new te emeter,

even in the case of a considerable change of' the distance of the object, only slight displacementsof 'the actuating mechanism of the toa tion in elevation' of the telemeter, those slig'lit improvements which correspond' to the slight deviat-ions in the height position of the object: 'If, however, an object which changes little its distance but, considerably itsheight, be concerned, it would be necesof the relative position of the two images, to dis lace the said actuating mechanism of the p anet' pinionby large amounts. said iii ,convenience is removed by providing the tlemeter, apart from the actuating.

mechanism of'the planet pinion, with an This conforms well to the.

(planet pinion are necessary, in order apt to the changes of the relative posi tion of the two images, caused by the rota-.

v the 'actuating mechanism 'of the planet p nion for the maintenance- The actuating mechanism, which is so coupled to the deflecting device, that to motions of the said actuatng mechanism there corre-` spond proportional motions of the deflecting device. For, only slight motions of the vdeflecting device being requisite for slight pinionis moving to and fro instead of making a rotatng moton.

'Finally,'the use of the invention does not 'only applyto those telemeters, containing the base-line within themselves, but in the same way to -telemeters, voperating with the baseline at the target. i

Figs. 2 and 3 of the annexed drawing represent 'as a con'struc'tional example the essential parts of a uniocular telemeter, 'containing the base-line within itself according to the invention. The body a of theftelcmeter is rotatably located in a fork b only partly shown in 'the drawing and provided at the bottom with a fastening pivot b ,The right entrance reflector system of thete-lemeter is formed by an optical squareprism 0 the right objective is marked c The members of the separating prism-sys-- tem are denoted by 0 and c those of the .ocular by c fland c The deflecting device of the telemeter consists of two refracti-ve wedges d and d The mount 8 of the wedge (i is provided with a bevel Wheel gearing f and the mount ez of the wedge d with a bevel wheel gearing f. A bevel wheel q engages in the said two gearings.

n A drum (1 isvfixed to the shaft g of the bevel wheel gand carries a range Scale g to which belongs a pointer 1 fitted to the body a A knob 9 serves for actuating the bevel wheel gUMoreover, in the geari'ngs f and f there engagesa bevel' wheel h carrying, within* a -bx a attached to the body a on its "sha'ft k a spur gear h -with spiralgearing. In the spur gear h there engages a spur gear z' which is located with its shaft 2' within the body a and which is also,provided With a spiralgea ing. On the shaft i there is rigidly mounted va bevel wheel 2' and loosely rotatable a drum j `Within the latter there is `rotatably disposed with the aid of 'a bolt j,

a bevel wheel j engaging in the bevel wheel 13 At its outer 'top margin the vdrum j carries 'a spur gear system j in Which engages a spur gear k located with its shaft 73 within the' 'box a and provided on the said shaft with a driving knob 70 At its outoms?? pointer j attached to the box a and which can be read ofl' through a window a To the fork b there is fixed a bevel wheel b embracing the body a and engaging in a bevel wheel Z located within the box a On the shaft Z of the said wheel there is fixed a spur gear Z with spiral gearing' With the spur gear Z meshes a spur gear m which is located with its shaft m within the box a and also provided with spiral gearing. In addition, on the shaft m there is fastened a bevel wheel m engarging in the bevel wheel j as well as a driving knob m With a view to adjusting the elevation, of the telemeter, the knob m rigidly connected to the bevel wheel m must be turned. Hereupon, with the aid of the spur gears m and l there rotatcs the bevel wheel P and consequently, whilst driving the body of the telemeter, drives the 'bevel wheel 71 The gearings of the spur gears m and l are so designed that the above mentioned relation always exists between the position of the bevel wheel m and the angle of sight of the direction of look out. A rotation of the knob 9 results in a relative rotation of the wedges d and d and, in addition, by means of the wheels h IL and z' in a rotation ot the bevel wheel The gearings of the spur gears h and 2' are so designed that. the aforesaid relation exists between the position of the bevel wheel i and the range indicated on the scale 0 The bevel wheel j forming conjointly with the bevel wheels i and m a dili'erential gear, assumes together with the drum j such a position that the height of the ohject of the measurement is indicated on the scale j* in each particular case, whilst the range is shown on the range scale 0 On the other hand, by holding fast the knob 1: so that the same height is continually indicated on the height scale j and by following up an object,'moving at the said height, by -rotating the telemeter about the pivot b and by turning the knob 771 the scale (1 always indicates correctly the continuously Variable range.

As, according to the abo-ve explanation,

the telemeter cannot on the one hand be constructed to an angle of sight of zero and up to an infinitelv long range as per the invention but, on the other hand, it being desirable to extend the observation to the said two limits, the constructional example has: been so devised that the telemeter can be adjusted according to the angle of sight zero and to the range infinity (vide the annexed drawing). without a correct indication of the elevation being thereby attained. For, at the end of the four spiral gearings circu lar gearings are provided for which will become operative when the angle of altitude and the range are approaching the said limits. By means of marks it can be indicated, when the circular gearings become operative. The indication of the range on the scale (1 is always correct.

lclaim:

1. The combination of a bearing body with a telemeter rotatably supported on this body, the telemeter comprising a deflecting de* vice, 'adapted to alter the relative position of two images of the object to be measured which are presented to the observer, a range scale and an index fitted to the telemeter relatively to one another, a differential gear fitted to the telemeter and comprising two crown wheels and a planet pinion, a gearing interposed between the said bearing body and one of the two crown wheels and adapted to convert a rotation of the telemeter relatively to the bearing body into a rotation of this crown wheel proportional to the logarthm of the sine of the angle of rotation of the telemeter reckoned from the horizontal direction of sight of the telemeter, another gearing interposed between the said deflecting device and the other crown wheel and adapted to convert the relative novenent of the range scale and the index into a rotation of the latter crown wheel proportional to the logarithm of the range indicated in each case on the range scale, and an actuating mechanism, adapted to rotate the said planet pinion about the common axis of the crown wheels.

2. The combination of a bearing body with a telemeter rotatably supported on this body, the telemeter comprising a deflecting device, adapted to alter the relative position of two images of the object to be measured which are presented to the observer, a range scale and an index fitted to the telemeter relatively to one another, a difi'erential gear fitted to the telemeter and comprising two crown wheels and a planet pinion having a logarithmic height scale and an index coacting with this height scale, a gearing interposed between the said bearing body and one ofthe two crown wheels and adapted to convert a rotation of the telemeter relatively to the bearing body into a rotation of this crown wheel proportional to the logarithm of the sine of the angle of rotation of the telemeter reckoned from the horizontal direction of sight of the telemeter, an-

-other gearing interposed between the said defiecting device and the other crown wheel and adapted to convert the relative movement of the range scale and the index into a rotation of the latter crown wheel proportional to the logarithm of the range indicated in each case on the range scale, and an actuating mechanism, adapted to rotate the said planet pinion about the common axis of the crown wheels.

3. The combination of a bearing body with a telemeter rotatably supported on this body, the telemeter comprising a deflecting device, adapted to alter the relative position y of two images of the object to be measured which are presented to the observer, a range Scale and an index fitted to the telemeter relatively to one another, a difl'erential gear fit-ted to the telemeter and comprisingtwo v crown wheels anda planet pinion, a gearing interposed between the said bearing body and one of the two crown wheels and adapted to convert a rotation of the telemeter relatively to the bearing bodyinto a rotation of this crown wheel proportional'to the logarithm of the sine of the a'ngle of 'rota- 'tion of the telemeter reckoned from the horizontal direction of sight of the telemeter, an actuating mechanismadapted to imp art to this crown wheel a motion roportional to the motion of the mechansm, another geuring interposed between the said deflecting device and the other crown wheeland adapted to convert the relative movement of the range Scale and the index into a rotation of the ltter crown wheel proper- .tional to 'the logarithm of the range indicated in each case on the range Scale, and an actuating mechanism, adapted to rotate the said' planet pinion about the common axis of the crown wheels.

4. The combination of a bearing body with a telemeter rotatably supported "on this body, the telemeter comprising a defiectng device, adapted to alter the relative position of two images of the object to be measured which are presented to the observer, a range Scale and an index fitted to the telemeter relatively to one another, a diflt'erential gear fitted to the telemeter and comprising two crown wheels and a planet pinion, a geuring w interposed between the said bearing body and one of the two crown wheels and adapted to convert' a rotation of the telemeter relatively to the bearing body into a rotaton of this crown wheel roportional to the logrelatively to the bearing body into a rotation of the telemeter reckoned from the horizon- V cated in each case on the range Scale, and an actu ating mechanism, adapted to r tate the said planet pinion about the common I axis of thecrown wheels, and another actuating mechanism adapted to impart to the. deflecting device a motion Proportional to the notion of this mechanism.

vOTTO EPPENSTEIN. Witnesses:

PAUL KRGER, RICHARD HAHN; 

